Method for robotic arms with strap drive trains

A method for a robotic arm, the method comprising:

• providing a linkage assembly including first, second, third, and fourth links coupled in series together with a strap drive train coupled thereto, the linkage assembly defining a parallelogram with an insertion axis, wherein the third link is a bent link including a bend configured to provide a compact robotic arm with an improved range of pitch;
• pitching the linkage assembly to alter a pitch angle of the insertion axis;
• ensuring the third link maintains the same angle relative to the first link in response to the pitching of the linkage assembly;
• and
• ensuring the fourth link maintains the same angle relative to the second link in response to the pitching of the linkage assembly.

A method for a robotic arm, the method comprising:

• adjusting a strap drive train to rotate an instrument holder link about a joint to calibrate a length in a long side of a parallelogram;
• adjusting the strap drive train to rotate a main link about a joint to substantially eliminate a remote center error;
• verifying that the length in the long side of the parallelogram is calibrated;
• and
• verifying that the remote center error is substantially eliminated.